RPC Exceptions observed with openflowplugin He design (tested with VTN)

Tested the VTN Openstack support. the instances were not reachable. When analyzing the log, Found exceptions when VTN Manager tries to invoke rpc's of openflowplgin.

:54:14,874 | ERROR | TN Flow Thread-0 | ClearNodeFlowsTask | 163 - org.opendaylight.vtn.manager.implementation - 0.4.0.SNAPSHOT | remove-flow: Caught an exception: canceled=false, input=RemoveFlowInput [_flowTable=FlowTableRef [_value=KeyedInstanceIdentifier

{targetType=interface org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.tables.Table, path=[org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.Nodes, org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.nodes.Node[key=NodeKey [_id=Uri [_value=openflow:121713027126083]]], org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.FlowCapableNode, org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.tables.Table[key=TableKey [_id=0]]]}

], _node=NodeRef [_value=KeyedInstanceIdentifier

{targetType=interface org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.nodes.Node, path=[org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.Nodes, org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.nodes.Node[key=NodeKey [_id=Uri [_value=openflow:121713027126083]]]]}

], _tableId=0, _transactionUri=Uri [_value=clean-up:openflow:121713027126083], _barrier=true, _strict=false, augmentation=[]]
java.util.concurrent.ExecutionException: org.opendaylight.controller.md.sal.dom.api.DOMRpcImplementationNotAvailableException: No local or remote implementation available for rpc AbsoluteSchemaPath

{path=[(urn:opendaylight:flow:service?revision=2013-08-19)remove-flow]}

at com.google.common.util.concurrent.AbstractFuture$Sync.getValue(AbstractFuture.java:299)[39:com.google.guava:18.0.0]
at com.google.common.util.concurrent.AbstractFuture$Sync.get(AbstractFuture.java:272)[39:com.google.guava:18.0.0]
at com.google.common.util.concurrent.AbstractFuture.get(AbstractFuture.java:96)[39:com.google.guava:18.0.0]
at org.opendaylight.vtn.manager.internal.util.rpc.RpcInvocation.getResult(RpcInvocation.java:82)[163:org.opendaylight.vtn.manager.implementation:0.4.0.SNAPSHOT]
at org.opendaylight.vtn.manager.internal.flow.remove.ClearNodeFlowsTask.uninstall(ClearNodeFlowsTask.java:178)[163:org.opendaylight.vtn.manager.implementation:0.4.0.SNAPSHOT]
at org.opendaylight.vtn.manager.internal.flow.remove.ClearNodeFlowsTask.run(ClearNodeFlowsTask.java:233)[163:org.opendaylight.vtn.manager.implementation:0.4.0.SNAPSHOT]
at org.opendaylight.vtn.manager.internal.util.concurrent.VTNThreadPool$WorkerThread.run(VTNThreadPool.java:400)[163:org.opendaylight.vtn.manager.implementation:0.4.0.SNAPSHOT]
Caused by: org.opendaylight.controller.md.sal.dom.api.DOMRpcImplementationNotAvailableException: No local or remote implementation available for rpc AbsoluteSchemaPath

{path=[(urn:opendaylight:flow:service?revision=2013-08-19)remove-flow]}

at org.opendaylight.controller.remote.rpc.RemoteRpcImplementation$1.onComplete(RemoteRpcImplementation.java:65)[138:org.opendaylight.controller.sal-remoterpc-connector:1.3.0.SNAPSHOT]
at org.opendaylight.controller.remote.rpc.RemoteRpcImplementation$1.onComplete(RemoteRpcImplementation.java:56)[138:org.opendaylight.controller.sal-remoterpc-connector:1.3.0.SNAPSHOT]
at akka.dispatch.OnComplete.internal(Future.scala:248)[124:com.typesafe.akka.actor:2.3.14]
at akka.dispatch.OnComplete.internal(Future.scala:245)[124:com.typesafe.akka.actor:2.3.14]

at akka.dispatch.japi$CallbackBridge.apply(Future.scala:172)[124:com.typesafe.akka.actor:2.3.14]
at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:32)[121:org.scala-lang.scala-library:2.11.7.v20150622-112736-1fbce4612c]
at scala.concurrent.impl.ExecutionContextImpl$AdaptedForkJoinTask.exec(ExecutionContextImpl.scala:121)[121:org.scala-lang.scala-library:2.11.7.v20150622-112736-1fbce4612c]
at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)[121:org.scala-lang.scala-library:2.11.7.v20150622-112736-1fbce4612c]
at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)[121:org.scala-lang.scala-library:2.11.7.v20150622-112736-1fbce4612c]
at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)[121:org.scala-lang.scala-library:2.11.7.v20150622-112736-1fbce4612c]
at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)[121:org.scala-lang.scala-library:2.11.7.v20150622-112736-1fbce4612c]